The present invention relates generally to pressurized fluid actuated motors and more praticularly to hydraulic actuated motors of the type adapted for use under water. More particularly, the present invention relates to a underwater hydraulic motor which is adapted for use under deep water.
Among various motors known in the art which are actuated by pressurized fluid, air motors which are actuated by compressed air and oil hydraulic motors which are actuated by hydraulic oil are in wide use. In accordance with a structual classification, the known motors include vane motors, plunger motors, turbine motors, etc., and these motors have been used effectively. However, these prior art motors give rise to many problems from the standpoints of performance, etc., when they are put in underwater applications. For instance, while the air motor has the advantage of being capable of discharging the exhaust into the water, where the normal service air pressure is used, the air motor can be used only under water of a limited depth. On the other hand, the oil hydraulic motor requires two supply and discharge pipes with the resulting complicated construction and moreover there is the danger of the hydraulic oil leaking and contaminating the surrounding water area.
While the use of an electric motor under water may be conceived, there is the disadvantage of requiring a complicated and large-sized mechanism for completely shutting off the entry of water into the motor and moreover there is the disadvantage of causing an electric shock by a leakage of electricity.